Austin (KXAN) — The 32nd annual CapTex Tri officially in the books. But among the athletes today, was a very special brother-sister duo who have faced many challenges together.

They were two of thousands taking on the triathlon on this Memorial Day.

The challenges they have faced at times much harder moments than the swimming, biking and running on the course.

“I had leukemia. I was diagnosed at 18 months old, and it was a blood leukemia. So I was diagnosed with AML and AOL, and I went through the chemotherapy, radiation therapy, and then basically was saved by my sister with the bone marrow transplant,” said Daniel Russell.

Daniel’s sister, Erin Boeckman is no stranger to triathlons and races. This is her 47th, but her first with her brother by her side.

“It’s a definitely a different experience, carrying an additional body and having to look out for, you know, him and safety and everything. But I feel really confident. I’ve been training for a while for this, and, yeah, I’m super excited to carry him through,” said Boeckman.

Russell said that support from his sister, his family and his friends is what motivates him to defy odds.

“Everything that I’ve done through my life, most people of my condition wouldn’t be able to do and I just I’ve defied the odds, and I continue to do that, even with my deteriorating condition,” said Russell.

Also by his side was his nephew.

“Another big motivation is my nephew. You know, I want to be the best uncle I can be for him,” said Russell.

With the support of two volunteers with para athletes by their side, and Erin’s husband and son, the team pushed through a 750-meter swim, a 12.3-mile bike ride, and a 3.1-mile run.

On Memorial Day, the brother-sister duo crossed the finish line together. Boeckman described the completion of the triathlon as a celebration of perseverance, love, and the unbreakable bond the two have built.

“Crossing the finish line with Daniel beside me was the greatest moment of my racing journey,” Boeckman said. “We’ve overcome so much together, from his battle with childhood leukemia to the day I became his bone marrow donor.”

Russell shared how he felt at the finish line festival.

“I may not have been the one running, but I felt like I was flying, especially on the bike!,” Russell said.

He expressed that his favorite part at the finish line was “feeling the wind and speed.” “The fact that my sister and I got to do this together, and cross the finish line as a team, means more to me than I can put into words,” Russell said.

“It’s a great community here in Austin. Having spent a bunch of time here, you see people up and down this path every day, all day long. And we’ve got a lot of those folks who are swimming, biking, and running today, and in part, to honor those who have served our country,” said Scott Nilson, the North American General Manager of SuperTri.

The CapTex Tri is the only triathlon in Austin where swimmers get to utilize Lady Bird Lake. Since its inception in 1991, it has always happened on Memorial Day.